The present invention pertains to a container suitable for packaging food items such as a pizza for carry-out which container comprises two complementary container pieces, which each have a sidewall provided with an upstanding tab portion and another sidewall, located adjacent the sidewall with the tab portion, provided with locking means formed from opposing boss portions adapted to interlock with the tab portion of a complementary container piece to securely close the container. The present invention also is related to a blank for forming each of the container pieces in accordance with the invention.
In the packaging art, emphasis has been placed on providing suitable containers which are easily stored so as to require minimum storage space, but which are usable immediately. Such a container would be particularly useful in the packaging of relatively large food items such as pizza for carry-out. A known type of container for pizza generally has a relatively large, rectangular bottom wall portion and a top wall portion having the same dimensions as the bottom wall. Four sidewalls are hingeably connected to the bottom wall. One of the sidewalls also hingeably connects the top wall to the bottom wall so that the top wall is provided in the form of a hinged cover for the container.
Other familiar boxes for pizza comprise the telescoping type. Such containers generally have two separate pieces with, one piece telescopically receiving the other piece. Where the pieces are of identical dimensions, the sidewalls could have special fold lines for permitting the covers of the piece which serves as the tray to be pinched inwardly so that the piece serving as the cover can be fitted thereover.
The above-described types of "fold-over" cover and two separate piece pizza boxes must be stored either as flat blanks or in squared-up condition. If flat blanks are stored, the blanks must be squared-up before their use and this increases the effort involved in the preparation of each food product for carry-out. On the other hand, if the boxes are stored in squared-up form, they must be stacked on top of each other and therefore require additional space.
In order to overcome the above-mentioned problems relating to storage of container pieces, nestable containers have been provided. For example, U.S. Pat. No. 3,027,062 discloses a combination tray and cover adapted for interlocking to contain an article. According to the patentee the tray and cover preferably are constructed from blanks of identical size and contour. The six walls of each try and cover piece include, located at the top edge thereof, a locking tab having a male portion delineated by a slit and a guide tab. To interlock the tray and cover, the cover is positioned over the tray so that the locking tabs of the two pieces are placed in contact. The cover is rotated with respect to the tray until the male portions of the locking tabs of each piece, lockingly engage in the slits of the other piece. The means for interlocking the two pieces of U.S. Pat. No. 3,027,062 are somewhat complicated in requiring rotation of the pieces with respect to each other to lock the two pieces together.
U.S. Pat. No. 4,362,265 is another example of a container having top and bottom members which are fabricated from a common blank so that they are reversible. Each tray is provided with a pair of upstanding, opposed end walls of one height and adjacent, upstanding, opposed sidewalls having a lower height. The trays are oriented with their openings facing and are rotated 90 degrees with respect to each other so that when they are brought together, the taller end walls of one tray overlap and telescope over the shorter end walls of the other piece.
U.S. Pat. No. 4,474,324 is a carton of the telescoping type wherein a cover piece fits over a tray piece. The common blank for forming each of the cover and tray pieces is provided with additional score lines so that the corners of the tray piece can be "pinched" together to permit the cover piece to slide over the sidewalls of the tray piece. Both U.S. Pat. Nos. 4,362,265 and 4,474,324 lack very reliable means for interlocking the identical container pieces to prevent accidental opening of the container.
In U.S. Pat. No. 4,444,354 there is shown yet another tray and telescoping cover formed from similar blanks. Still other containers and food cartons are shown in U.S. Pat. Nos. 3,926,362; 4,431,128; 4,339,068; and 4,470,538.